Technical Field
Embodiments of the invention relate generally to rendering ultrasound images. Particular embodiments relate to fetal ultrasound imaging.
Discussion of Art
Ultrasound medical imaging is typically used to survey internal structures for diagnostic purposes. Ultrasound has several unique features including comparatively short image acquisition times, on the order of one half second compared to several seconds for MRI, the ability to acquire many images with minimal patient risk, and an interactive role for a technician as part of the imaging system control loop. As a result, ultrasound is particularly useful for imaging moving internal structures, e.g., for fetal imaging during gestation.
With reference to fetal imaging, ultrasound serves more than merely diagnostic purposes. The presentation of a live image to prospective parents can promote emotional bonding of parents to their offspring, and enhance motivation to comply with well-baby practices recommended by obstetric professionals. Moreover, it is pleasing for prospective parents to feel that they are seeing how things appear within the womb. As will be appreciated, womb and fetal images, and, indeed, all ultrasound images that display a high degree of realism are desirable.
In fetal ultrasound, amniotic fluid has conventionally been treated as a completely transparent medium that does not affect light or produce any scattering or refraction effects. This treatment has been achieved by setting the opacity function, for scalar values below the threshold of amniotic fluid, to zero. As a result, amniotic fluid is not accounted for during image rendering. Failure to account for amniotic fluid, however, could potentially result in images that are less than realistic. For example, amniotic fluid scatters “light” (ultrasound) around the fetus. Also, the chemical composition of amniotic fluid, mainly lipids, causes strong specular highlights on fetal skin.
In view of the above, it is desirable to provide apparatus and methods for enhancing the realism of a fetal image, and, in particular, for representing amniotic fluid in an ultrasound image.